In recent decades, automobile industry develops rapidly. With performances of automobiles developing towards a safer, more reliable, more stable, fully-automatic and intelligent, and environmental friendly and energy saving trend, electrically driven centrifugal pumps have gradually replaced the conventional mechanical centrifugal pumps, and are widely applied in automobile heat management or circulation systems. The electrically driven centrifugal pumps have advantages of having lower electromagnetic interference, high efficiency and environmental protection, stepless speed regulation, etc. thus can well meet requirements of market.
The electrically driven centrifugal pump includes a stator assembly and a rotor assembly, the stator assembly and the rotor assembly are fully isolated by a partition, which avoids the issue of liquid leakage existing in the conventional motor type centrifugal pump. Currently, the rotor assembly of the electrically driven centrifugal pump includes an impeller and a rotor, and in a conventional design, the rotor assembly is an integrally formed part, i.e., the impeller and the rotor are formed by injection molding. The rotor assembly is formed by injection molding using a mixed material of a plastic material and a magnetic material or plastic material, and taking a shaft sleeve as a base member for the injection molding, thus the shaft sleeve is generally formed in advance. The shaft sleeve is generally arranged to be rotatable with respect to the shaft, and also is covered by the material of the impeller, therefore, the structure of the shaft sleeve influences the intendity of the connection of the shaft sleeve to the impeller.